Thanks to Stringy and Kirk I was finally able to put the photos online.

The mast step is the tube for the factory step inserted into a thwart and base I made from white oak.

My trailer is made from a beach cart plus two aluminum tubes covered with pipe foam insulation. My recumbent trike has 63 gears, so no problem towing it to the ramp 0.8 miles (1.28 km) from my home.

I plan to order the 45 inch crossbar so that I may experiment with up to 7 foot maximum spacing for the amas. That will be the same proportion as the Adventure Island Trimaran which has 9 foot spacing for the amas with a 16 foot main hull. My old 2000 Classic Hobie is 13 foot long, so I calculated 7 foot might be ok.